Known microcomputer based systems, such as electricity meters, utilize a basic master oscillator and a slower subclock oscillator. The subclock oscillator generates a signal having a frequency much lower than the basic master oscillator. Both the master oscillator and the subclock oscillator are crystal controlled.
Upon reset of the microcomputer (e.g., upon power-up), it is important that both the master oscillator and the subclock oscillator begin operating (i.e., oscillating) almost immediately. In an electricity meter, for example, such immediate operation is necessary in order to ensure a proper start-up and measurement of energy consumption. Low frequency oscillators, however, typically have a slow start-up time. Such slow start-up time may interfere with the desired operation of the meter which, of course, is undesirable.
Accordingly, it would be desirable to provide methods and apparatus for controlling operation of a low frequency oscillator so that such oscillator has a fast start-up time, at least as compared to the start-up times of known low frequency oscillators. Such methods and apparatus also preferably will not add significant costs in terms of components and circuit assembly time.